GEMS Kits utilize the latest and best materials to create the most durable and best engineered planes available. Among these materials are “GEMS Spar and GEMS Stringer” which will not break, crack, splinter or shatter like other systems out there. There is no weight penalty either and we are the only ones who have it in our planes. Learn more about the kit at: http://www.slopeslayer.com/wordpress/?page_id=50